1. Field of the Invention
This invention relates to an ink jet recording head, which effects recording with fine droplets of a recording solution, generally known as ink, discharged from a fine port and ejected onto a record face to be attached thereto, and more particularly to a method for producing an ink jet recording head finished so as to be water-repellent in such a way to have a hydrophilic section around the ink discharge port, and to an ink jet recording head produced by the same method.
2. Related Background Art
An ink jet recording head is generally equipped with a fine ink discharge port, liquid passage, and discharge energy generating section provided in part of the liquid passage. It is known that discharge stability is generally enhanced by making the head water-repellent around the ink discharge port.
However, printing quality is sometimes degraded, when an ink discharge port is finished so as to be water-repellent at its face front. It is found that this phenomenon results from poor discharge caused by that when a large quantity of ink is present on the ink discharge port face, it moves to the discharge port.
Therefore, the face that is finished so as to be water-repellent is partly provided with a hydrophilic section, which holds ink to prevent its migration.
Such a hydrophilic section is formed by various methods, e.g., laser ablation in which a water-repellent processed layer formed is partly irradiated with laser beams to remove the part, and another method known as photolithography process in which a water-repellent light-sensitive resin layer, formed on the ink discharge port face, is selectively exposed to light and developed.
The above methods to form the hydrophilic section involve the following problems;
(1) an expensive irradiation is needed,
(2) another step is needed for the water-repellent finishing, needing a changeover of setup,
(3) adjustment of the irradiation is complicated, or
(4) irregularities are formed on the ink discharge port surface, possibly holding waste in the cavities to cause wiping problems.
The present invention is made in view of the above problems. It is an object of the present invention to provide a method for producing an ink jet recording head, which is free from the above problems, produced by an inexpensive system, and excellent in discharge stability. It is another object of the present invention to provide an ink jet recording head produced by the same method.
The above problems can be solved, and the objects can be achieved by the present invention described in detail below.
The present invention provides a method for producing an ink jet recording head equipped with an ink discharge port from which the ink is discharged, an ink discharge port face on which the ink discharge port is set and an discharge energy generating element which generates energy necessary to discharge the ink, and is finished so as to be water-repellent in such a way to make the ink discharge port face partly hydrophilic around the ink discharge port, comprising the following steps:
a step which forms the photosensitive water-repellent processing layer on the ink discharge port face,
a step which irradiates light onto the water-repellent forming region and hydrophilic forming region in the water-repellent processing layer, to cure the layer,
a step which further irradiates light selectively onto the hydrophilic forming region to reduce water repellency of the water-repellent processing layer and to impart hydrophilicity to the hydrophilic forming region, and
a step which forms an opening, which constitutes a part of the ink discharge port, in the water-repellent processing layer.
The present invention also provides the ink jet recording head produced by the above method.
The present invention also provides a method for producing an ink jet recording head equipped with an ink discharge port from which the ink is discharged, an ink discharge port face on which the ink discharge port is set and a discharge energy generating element which generates energy necessary to discharge the ink, and is finished so as to be water-repellent in such a way to make the ink discharge port face partly hydrophilic around the ink discharge port, comprising the following steps:
a step which forms the photosensitive water-repellent processing layer on the ink discharge port face,
a step which irradiates light onto the water-repellent forming region in the water-repellent processing layer, to cure the layer,
a step which irradiates light in a quantity in excess of the level required for curing the water-repellent processing layer onto the hydrophilic forming region to reduce the water repellency of the water-repellent processing layer and to impart hydrophilicity to the hydrophilic forming region, and
a step which forms an opening, which constitutes a part of the ink discharge port, in the water-repellent processing layer.
The present invention also provides the ink jet recording head produced by the above method.